Sharepoint Tutorials about Large List and Unique Columns

This Sharepoint 2013 or 2010 example is about how we can work with how you can work with large lists and what unique columns look like.SharePoint
2013 has support for very large lists of up to 50 million items. With this
expanded list size comes the ability to throttle and control how much data is
returned to the user and prevent large queries from compromising the SharePoint
farm.

For this demo we have created a console application named FillUpLargeList. Open a command window and navigate to it.

Execute
the console application by specifying the URL to your SharePoint site and the
name of the list you want to populate with 6000 items.

we need to create a console application
that creates a large list with 6000 items in it.

The List Settings page will warn you that the threshold of 5000 items
is exceeded.

When the list has a large number of items but
hasn’t reached the threshold yet, the bar will warn you that the list is not
throttled yet but that the list has passed the warning level.

Open an Internet browser and navigate to the LargeList in your SharePoint site.

Navigate to the List Settings page and notice the extra section under the list
description telling that the list contains 6000 items while the threshold is
5000 items

The demo console application will query a large list with a
number of items that exceeds the threshold. This will work when you are logged
in as the administrator.

You can disable the throttling on a list by setting
the EnableThrottling property to
false.

Open the ListThrottling
project from the starter files in Visual Studio 2010.

This console application will query the LargeList list.

The largeList.Items method will throw an error when
logged in as a regular user but will be executed when logged in as
administrator.

static void Main(string[] args)
{
SPListItemCollection items;
// get reference to site passed in as an argument
using (SPSite siteCollection = new SPSite(
"http://intranet.contoso.com/sites/ListsAndSchemas"))
{
SPList largeList =
siteCollection.RootWeb.Lists["LargeList"];
// if logged in as a regular user, the following
// would throw an exception
// if the list contained more than 5000 items...
items = largeList.Items;
Console.WriteLine(items.Count);
// the following will disable the throttling on
// the list
largeList.EnableThrottling = false;
largeList.Update();
items = largeList.Items;
Console.WriteLine(items.Count);
}
}

If you want to check whether a list is throttled before executing a query, you can test upon the IsThrottled property of the list.You can add the following code to check whether the list is
throttled or not.

It
is not a good idea to test on the number of items in the list because you don’t
know what the throttling setting is in the web application.You
can also decide to put the throttle off.Set the EnableThrottling
property of a SPList object off to
disable throttling:

This
code can run under a normal user account.Open the Windows
PowerShell V2 (CTP3) command shell.Execute the SharePoint snap-in to load the SharePoint
assemblies:Add-psSnapin Microsoft.SharePoint.Powershell.Define a variable for the site collection using the
PowerShell cmdlet get-SPSite:

$sitecol = get-SPSite http://intranet.contoso.com

The settings about throttling are not set at site collection
level but at web application level. The WebApplication
property will return the web application. To get all properties of the WebApplication, you can run the
following command:

$sitecol.WebApplication | select *

The property MaxItemsPerThrottledOperation
returns the upper limit:

$sitecol.WebApplication.MaxItemsPerThrottledOperation

You can also check the property MaxItemsPerThrottledOperationOverride how far you can override this
limit. In this case super users are able to execute queries up to 20000 items:

You can also check if it is allowed to override the
throttling settings:

To check the properties of a specific list, you can execute
the following PowerShell command:

$sitecol.RootWeb.Lists[“LargeList”]

The property concerning throttling is the IsThrottled property, indicating
whether the list is throttled or not.